PROCESS FOR PREPARING (CYCLOPENTYL[d]PYRIMIDIN-4-YL)PIPERAZINE COMPOUNDS

ABSTRACT

The present disclosure relates to processes for preparing (cyclopentyl[d]pyrimidin-4-yl)piperazine compounds, and more particularly relates to processes for preparing (R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d] pyrimidin-4-yl)piperazine and N-protected derivatives thereof, which may be used as an intermediate in the synthesis of Ipatasertib (i.e., (S)-2-(4-chlorophenyl)-1-(4-((5R,7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazin-1-yl)-3-(isopropylamino)-propan-1-one). The present disclosure additionally relates to various compounds that are intermediates employed in these processes.

PRIORITY OF INVENTION

This application is a continuation of U.S. patent application Ser. No.15/514,188, filed Mar. 24, 2017, which is a national phase entry ofInternational Patent Application No. PCT/US2015/052143, filed Sep. 25,2015, which claims the benefit of priority U.S. Provisional ApplicationNo. 62/055,893, filed 26 Sep. 2014, the contents of each of which areincorporated herein by reference in their entireties.

FIELD OF THE DISCLOSURE

The present disclosure relates to processes for preparing(cyclopentyl[d]pyrimidin-4-yl)piperazine compounds, and moreparticularly relates to processes for preparing(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine and N-protected derivatives thereof, whichmay be used as an intermediate in the synthesis of Ipatasertib (i.e.,(S)-2-(4-chlorophenyl)-1-(4-((5R,7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazin-1-yl)-3-(isopropylamino)-propan-1-one).The present disclosure additionally relates to various compounds thatare intermediates employed in these processes.

BACKGROUND OF THE DISCLOSURE

AKT (also known as Protein Kinase B) is a serine/threonine proteinkinase that is overexpressed in certain human tumors. Ipatasertib is anAKT inhibitor that is currently being evaluated in clinical trials forthe treatment of solid tumors, gastric cancer, and prostate cancer.Ipatasertib is disclosed in, for example, U.S. Pat. No. 8,063,050 (see,e.g., Example 14), as well as International Patent ApplicationPublication No. WO 2008/006040.

(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine, or the N-protected derivative thereof, may be used as anintermediate in the synthesis of Ipatasertib. Processes for preparingthis intermediate are reported in, for example, International PatentApplication Publication No. WO 2013/173736 and International PatentApplication Publication No. WO 2013/173768. Scheme 1 of WO 2013/173768is shown below:

The present disclosure provides improved processes for the large-scalemanufacturing of (cyclopentyl[d]pyrimidin-4-yl)piperazine compounds, andmore particularly(R)-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine,as well as N-protected derivatives thereof. As compared to currentlyknown processes, the processes of the present disclosure advantageouslyprovide improvements in, for example, process conditions, reagentselection, complexity of required unit operations, scalability, and thelike.

SUMMARY OF THE DISCLOSURE

The present disclosure provides improved processes for preparing(cyclopentyl[d]pyrimidin-4-yl)piperazine compounds, and moreparticularly(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine,as well as N-protected derivatives thereof, such as for exampletert-butyl-(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate.The present disclosure further provides processes for preparing AKTinhibitors, and in particular Ipatasertib, using such improved processesfor preparing these (cyclopentyl[d]pyrimidin-4-yl)piperazine compoundsand N-protected derivatives thereof.

In one embodiment, the present disclosure is directed to a process forpreparing a compound of Formula I:

or a salt thereof, the process comprising contacting a compound ofFormula III:

or a salt thereof, with a metalating agent to form the compound ofFormula I, or a salt thereof, wherein R¹ is hydrogen or an aminoprotecting group.

In this or another embodiment, the present disclosure is furtherdirected to such a process, wherein the compound of Formula III, or asalt thereof, is prepared by contacting a compound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group.

In this or yet another embodiment, the present disclosure is stillfurther directed to such a process, wherein the compound of Formula IV,or a salt thereof, is prepared by brominating a compound of Formula V:

or salt thereof; wherein each X is independently selected from chloroand hydroxyl. In one particular embodiment, the present disclosure isdirected to such a process wherein the compound or salt of Formula IV isnot isolated after the bromination of the compound or salt of Formula Vand prior to reaction with the piperazine compound, as detailed above.

In this or yet another embodiment, the present disclosure is stillfurther directed to such a process, wherein the compound or salt ofFormula IV (wherein Y is Br) is prepared by brominating a compound ofFormula V_(b):

or a salt thereof, to form the compound or salt of Formula IV.Alternatively, the compound or salt of Formula IV (wherein Y is Cl, ormore particularly Br) is prepared by chlorinating the compound ofFormula V_(b), or a salt thereof, to form a compound of Formula V_(c):

or a salt thereof; and, brominating the compound or salt of FormulaV_(c) to form the compound of Formula IV, or salt thereof. In oneparticular embodiment, the present disclosure is directed to such aprocess wherein the compound or salt of Formula V_(b) is not isolatedafter the chlorination of the compound or salt of Formula V_(b) andprior to bromination.

In this or yet another embodiment, the present disclosure is stillfurther directed to such a process wherein the compound or salt ofFormula V_(b) is not isolated after the chlorination of the compound orsalt of Formula V_(b) and prior to bromination to form the compound orsalt of Formula IV, and further that the compound or salt of Formula IVis not isolated after the bromination of the compound or salt of FormulaV_(b) and prior to reaction with the piperazine compound to form thecompound or salt of Formula III.

In this or yet another embodiment, the compound or salt of Formula V_(b)is prepared by cyclizing a compound of VI_(b):

or a salt thereof.

In this or yet another embodiment, the compound of Formula IV_(b), or asalt thereof, is prepared by (i) contacting crotononitrile with malonateto form an isomeric mixture comprising a compound of Formula VI_(a) andthe compound of Formula VI_(b):

or salts thereof, and then (ii) separating the compound or salt ofFormula VI_(b) from the compound or salt of Formula VI_(a) in theisomeric mixture. In one particular embodiment, the compound of FormulaVI_(b), or salt thereof, is separated from the isomeric mixture byenzymatic resolution. In this or another particular embodiment, theisomeric mixture is not isolated from a reaction production mixtureresulting from contacting crotononitrile with malonate, prior toseparation of the compound of Formula VI_(b), or salt thereof; that is,the compound of Formula VI_(b), or salt thereof, is separated directlyfrom the reaction product mixture.

In yet another embodiment, the present disclosure is still furtherdirected to a process for preparing a compound of Formula IX:

or a salt thereof, wherein R² is hydrogen or an amino protecting group,the process comprising: (i) contacting a compound of Formula III,

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group,with a metalating agent to form a compound of Formula I:

or salt thereof; (ii) reducing the compound of Formula I, or a saltthereof, to form a compound of Formula VII_(a):

or salt thereof; (iii) optionally deprotecting the compound of FormulaVII_(a), or salt thereof, to form a compound of Formula VII_(b):

or salt thereof; and (iv) contacting the compound of Formula VII_(b), orsalt thereof, with a compound of Formula VIII:

or salt thereof, to form the compound of Formula IX, or salt thereof.

In yet another embodiment, the present disclosure is still furtherdirected to a compound of Formula V_(b):

or salt thereof.

In yet another embodiment, the present disclosure is still furtherdirected to a compound of Formula V_(b):

or salt thereof.

In yet another embodiment, the present disclosure is still furtherdirected to a compound of Formula IV_(b):

or salt thereof.

In yet another embodiment, the present disclosure is still furtherdirected to a compound of Formula IV_(c):

or salts thereof.

In yet another embodiment, the present disclosure is still furtherdirected to a compound of Formula III:

or salt thereof, wherein R¹ is hydrogen or an amino protecting group.

Optional modifications for one or more of the above embodiments, as wellas additional details related thereto, are further provided hereinbelow.

DETAILED DESCRIPTION OF THE DISCLOSURE

As further detailed herein below, the present disclosure is generallydirected to an improved process for preparing(cyclopentyl[d]pyrimidin-4-yl)piperazine compounds, and moreparticularly is directed to improved processes for preparing(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine,as well as n-protected derivatives thereof, such as for exampletert-butyl-(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate,as generally illustrated in scheme 2, below:

With respect to Scheme 2, it is to be noted that the dihydroxy-nitrilepyrimidine may be directly brominated, or alternatively may be firstchlorinated, the resulting chlorinated reaction product beingsubsequently brominated.

It is to be further noted, with respect to Scheme 2, that one or more ofthe compounds illustrated therein may be prepared and/or utilized in aparticular isomer or stereochemical configuration, or alternatively maybe prepared and/or utilized as a racemate or a mixture of stereoisomers.In one particular embodiment, however, the R-isomer of one or more ofthe reaction products is prepared or isolated using means generallyknown in the art and/or as further detailed herein, and optionallyfurther used in any subsequent reaction step. For example, enzymaticresolution may be used to preferentially obtain the R-isomer of theconjugate addition reaction product (compound of Formula VI_(b)), theR-isomer then being used in subsequent reaction steps, as furtherillustrated in Scheme 3, below:

Advantageously, the present process eliminates the need for aniodination step and/or the use of an iodide-containing reagent therein,thus being more cost-effective and environmentally-friendly than otherprocesses which utilize them. In particular, the present processinvolves a cyclization or ring closure reaction step to form thecyclopentyl ring of the compound of Formula I that utilizes abromo-nitrile substituted compound of Formula III, rather than forexample an iodo-ester, an iodo-acid or an iodo-amide substitutedanalogue compound. As further illustrated by the comparative resultsprovided herein below (see, e.g., Example 6), experience to-datesuggests that the cyclization or ring closure reaction is less effectivewhen the chloro-nitrile substituted analogue compound is used.

The present process further allows for (i) a more reactive or strongerbrominating agent, and/or (ii) more harsh or a broader range ofhalogenation reaction conditions (e.g., higher reaction temperatures),to be used to carry out the bromination step, due to the presence of thenitrile moiety in, for example, the compounds of Formula V_(b) andFormula V_(c). In contrast, use of such a brominating agent and/or suchharsh reaction conditions to prepare a bromo-ester substituted analogcompound results in ester-cleavage and concomitant lactone formation.

The present process is still further advantageous, inasmuch as properselection of the brominating agent used in the bromination reaction stepresults in the formation of volatile byproducts that can be removed bydistillation. In this regard, it is generally believed that removal ofthese byproducts from the mixture, as the reaction is carried out,enables the reaction equilibrium to be better controlled, such that thereaction favors bromine exchange at both locations; that is, in forexample Scheme 3 above, both chlorine atoms in the compound of FormulaV_(c), or hydroxyl moieties in the compound of Formula V_(b), arereplaced by bromine. Such a process enables greater conversion to thedesired reaction product (i.e., the compound of Formula IV_(b)), andreduces the amount of impurities that would otherwise be present in thereaction mixture.

The present process is still further advantageous, inasmuch asbromination of the nitrile-substituted compound of Formula V_(c) enablesfewer equivalents of the brominating agent to be used in comparison, forexample, to equivalents of an iodinating agent, in an iodinationreaction of an ester-substituted analogue compound as illustrated inScheme 1 above (e.g., iodination of Compound 1.1 to Compound 1.2).

The present process is still further advantageous, inasmuch as reactionof the bromo-nitrile substituted compounds of Formula IV_(b) and FormulaIV_(b) with the piperazine compound may be carried out at lowertemperatures, and in particular at about room temperature, as compared,for example, to reaction of the iodo-ester substituted analoguecompounds with the piperazine compound as illustrated in Scheme 1 above(e.g., Compound 1.2 to Compound 1.3), which is typically carried out at60° C. Lower reaction temperatures advantageously allow for theconservation of energy, and/or reduce the potential of unwantedbyproduct formation.

The present process is still further advantageous, inasmuch as itenables one or more of the reaction steps to be carried out in athrough-process manner, thus eliminating the need for isolation of anintermediate reaction product before one or more subsequent reactionsteps are carried out. In particular, (i) the reaction product of thebromination step (i.e., compounds of Formulas IV_(b) and IV_(c)) neednot be isolated prior to reaction with the piperazine compound, and/or(ii) the reaction product of the chlorination step (i.e., compound ofFormula V_(b)) need not be isolated prior to the bomination step, and/or(iii) the reaction products of the conjugate addition step (i.e.,compounds of Formulas VI_(a) and VI_(b)) need not be isolated from areaction product mixture comprising them prior to separation (by, e.g.,enzymatic resolution).

In one particular embodiment of the present process, all of theabove-noted through-process advantages are utilized, in order to reducethe duration of the overall production cycle (as illustrated, forexample, in Scheme 3) by about 20%, about 30%, about 40%, about 50%,about 60%, or more, as compared for example to such a process that doesnot utilize these through-process advantages to prepare an estersubstituted analog compound (as illustrated, for example, in Scheme 1).Furthermore, in this particular embodiment, the compound of formulaV_(c) is not isolated before bromination, the bromination reaction beingcarried out using a more reactive brominating agent and more harshbromination reaction conditions, as further detailed herein. Stillfurther, the bromination reaction is carried out with distillation ofthe volatile reaction byproducts. Still further, the isomeric mixturecomprising the compounds of Formulas VI_(a) and VI_(b) is not isolatedfrom the reaction product mixture before being subject to enzymaticresolution. Still further, the bromo-nitrile substituted compounds ofFormulas IV_(b) and IV_(c) are reacted with the piperazine compound atabout room temperature.

The present disclosure is still further directed to one or more of theintermediate reaction products or compounds, or salts thereof, preparedby the process.

A. (Cyclopenta[d]pyrimidin-4-yl)Piperazine Compounds 1. Cyclization Step

In one embodiment, the present disclosure is directed to a process forpreparing a compound of Formula I:

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group.The process comprises contacting a compound of Formula III:

or a salt thereof, with a metalating agent to form the compound ofFormula I, or a salt thereof, wherein R¹ is hydrogen or an aminoprotecting group. More particularly, the process comprises contactingthe compound of Formula III, or a salt thereof, with a metalating agentto form a compound of Formula II:

or a salt thereof, wherein R¹ is as previous defined and M is a metal ortransition metal (such as lithium or magnesium) as further detailedbelow, and then cyclizing the compound of Formula II, or a salt thereof,to form the compound of Formula I, or a salt thereof.

In certain embodiments, R¹ is an amino protecting group, as definedelsewhere herein below. In one or more particular embodiments, R¹ may beselected from phthalimidyl, benzyl, triphenylmethyl, benzylidenyl,p-toluenesufonyl, and p-methoxybenzyl. R¹ may also be selected from—C(O)—R^(d) or —C(O)OR^(d), wherein R^(d) is independently selected fromhydrogen, substituted or unsubstituted alkyl, substituted orunsubstituted alkenyl, substituted or unsubstituted alkynyl, substitutedor unsubstituted cycloalkyl, substituted or unsubstituted phenyl orsubstituted or unsubstituted heterocyclyl. Exemplary embodiments includethose wherein R¹ is: (i) —C(O)OR^(d), and further wherein R^(d) ist-butyl, benzyl or fluorenylmethyl (that is, R¹ is t-butoxycarbonyl(BOC), benzyloxycarbonyl, or fluorenylmethyloxycarbonyl (FMOC)); or,(ii) —C(O)R^(d), and further wherein R^(d) is methyl or trifluoromethyl(that is, R¹ is acetyl or trifluoroacetyl). In alternative exemplaryembodiments, R¹ is —C(O)OR^(d) or —C(O)R^(d), wherein R^(d) is selectedfrom hydrogen and C₁-C₁₀ alkyl, and further wherein said alkyl isoptionally substituted by an oxo, halo or phenyl moiety. In certainpreferred embodiments, R¹ is selected from acetyl, trifluoroacetyl,phthalimidyl, benzyl, triphenylmethyl, benzylidenyl, p-toluenesulfonyl,p-methoxybenzyl, tertbutyloxycarbonyl, 9-fluorenylmethyloxycarbonyl andcarbobenzyloxy.

The metalating agent, which is understood to encompass metals andtransition metals, may in general be selected from any metalating agentthat facilitates cyclization or ring closure to form the cyclopentylring. Typically, the metalating agent is an organometal compound, whichmay for example comprise one or more of lithium and magnesium, and/or ahalogen. More particularly, the metalating agent may be an organolithiumcompound or reagent (e.g., R^(x)Li), an organomagnesium compound orreagent (e.g., R^(x)MgZ), or an organomagnesium-lithium compound orreagent (e.g., (R^(x))₃MgLi), wherein: (i) each R^(x) present isindependently selected from optionally substituted C₁₋₁₀ alkyl,optionally substituted C₃₋₇ cycloalkyl, optionally substituted aryl,optionally substituted heteroaryl, or optionally substitutedheterocyclyl, or two R^(x) groups are taken together with the atom towhich they are attached to form a 5-7 membered, optionally substitutedring; and, (ii) Z is a halogen, and more particularly is Cl, Br or I. Insome embodiments, each R^(x) is independently selected from optionallysubstituted C₁₋₁₀ alkyl and optionally substituted C₃₋₇ cycloalkyl, butmore particularly is selected from isopropyl (iPr) or butyl (n-butyl,sec-butyl or t-butyl). Optionally, an additive that acts to modulate thereactivity and/or the stability of the metalating agent may also be used(e.g., an amine, and more specifically a diamine, additive or modifier).

Exemplary organomagnesium compounds or reagents include Grignardreagents like C₁-C₆ alkylmagnesium halides, and more particularlyinclude iPrMgCl or sec-butylMgCl, which may be used alone or as part ofa lithium chloride complex (e.g., iPrMgCl.LiCl). (See, e.g., Organomet.Chem., 2011, 37, 1-26, pp. 7-13; and, A. Krasovskiy and P. Knochel,Angew. Chem., Int. Ed., 2004, 43, 333.) Exemplary organolithiumcompounds or reagents include C₁-C₆ alkyllithium, and more particularlyinclude n-butyllithium, sec-butyllithium and t-butyllithium. Exemplaryorganomagnesium-lithium compounds or reagents (i.e., (R^(x))₃MgLi),include those wherein R^(x) is C₁-C₆ alkyl, and more particularly is forexample isopropyl or butyl (e.g., n-butyl, sec-butyl or t-butyl), suchcompounds including lithium tri-n-butylmagnesiate, lithiumtriisopropylmagnesiate, and lithium (isopropyl)(di-n-butyl)magnesiate.

Although the particular process conditions, including one or more ofreaction time, temperature, solvent, reagent, amount of reagent(s),order of reagent addition, pH, etc. may be selected in order to optimizereaction product purity and/or yield, in particular the compound ofFormula III may be contacted with from about 1 to about 1.5 molarequivalents of the metalating agent, and more particularly from about 1to about 1.4, or from about 1.05 to about 1.2, molar equivalents of themetalating agent. Additionally, in one particular embodiment, the actionof combining or contacting the compound of Formula III with themetalating agent may occur over a period of time or in stages duringthis reaction step, the amount and/or timing of each addition beingdetermined in order to optimize yield and/or purity, and/or to ensurethe final addition occurs near the end of the reaction time. Forexample, the metalating agent may be added in about equal portions tothe reaction mixture containing the compound of Formula III over aperiod of time (e.g., about 4 hours), the final portion thereof beingadded near the end of the desire reaction time.

In various embodiments, the process for preparing the compound ofFormula I, or a salt thereof, may be carried out in an ethereal orhydrocarbon solvent, or a mixture of these solvents (e.g.,tetrahydrofuran (THF), 2-methyltetrahydrofuran (MeTHF), methyltert-butyl ether (MTBE), cyclopentyl methyl ether (CPME), diethyl ether,diisopropyl ether, diphenyl ether, toluene, ethylbenzene, xylene,cumene, pentane or heptane). Exemplary reaction conditions include: (i)a reaction temperature of about 20° C., about 15° C., about 10° C.,about 5° C., about 0° C., or less (e.g., about −10° C., about −25° C.,about −50° C., or about −75° C.); and/or (ii) carrying out the reactionunder substantially anhydrous conditions (e.g., about 100 ppm, about 50ppm, about 25 ppm, or about 10 ppm water, or less); and/or (iii)carrying out the reaction under an inert atmosphere (e.g., under ahelium, neon, argon or nitrogen atmosphere). In a particular embodiment,a process for preparing a compound of Formula I, or a salt thereof, froma compound of Formula III, or salt thereof, is carried out in MeTHF,alone or in combination with toluene, at a temperature of from about−15° C. to about 15° C., from about −10° C. to about 10° C., or fromabout 0° C. to about 5° C., optionally under anhydrous conditions and/oroptionally under an inert (e.g., nitrogen) atmosphere.

Additionally, it is to be understood that further processing or work upof one or more of the resulting products from the above-note cyclizationor ring closure reaction may be performed, in order to obtain thedesired final product (i.e., the compound of Formula I) using meansknown in the art, such as for example hydrolysis of an enamine reactionintermediate to obtain the final ketone product. See, e.g., WO2013/173784, the contents of which are incorporated by reference for allrelevant and consistent purposes.

In various embodiments, conversion or cyclization of the compound ofFormula III to the compound of Formula I is about 90%, about 95%, about99% or more, and/or the yield of the compound of Formula I is about 75%,about 80%, about 85%, about 90% or more.

2. Piperazine Addition Step

In one embodiment, the compound of Formula III, or a salt thereof, isprepared by contacting a compound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group, both as defined elsewhere herein below. In anexemplary embodiment, Y is bromo. In this or another exemplaryembodiment, R¹ may be, for example, alkoxycarbonyl (such ast-butoxycarbonyl) or aryloxycarbonyl (such as benzyloxycarbonyl). Inthese or other exemplary embodiments, Lv may be, for example, hydrogenor halogen. Alternatively, however, one or both of R¹ and Lv may beselected from among the other options recited in the definitionsprovided elsewhere herein below, or alternatively from amino protectinggroups and leaving groups known to those of skill in the art, withoutdeparting from the intended scope of the present disclosure.

Although the particular process conditions, including reaction time,temperature, solvent, reagent, amount of reagent(s), order of reagentaddition, pH, etc. may be selected in order to optimize reaction productpurity and/or yield, in particular the compound of Formula IV may becontacted with from about 1 to 1.5 molar equivalents of the piperazinecompound, and more typically will be contacted with from about 1.05 toabout 1.4, or from about 1.1 to about 1.2, molar equivalents of thepiperazine compound, with about 1.15 equivalents of the piperazinecompound being used in one particular embodiment.

In this regard it is to be noted that reaction temperature and/or theamount of the piperazine compound added, among other considerations(e.g., type and/or amount of base added or solvent used), will typicallybe controlled or optimized in order to limit the amount of adi-piperazine substituted reaction byproduct being formed (i.e., theformation of a compound wherein both bromine atoms are displaced by orexchanged with the piperazine compound). For example, in one or moreembodiments the reaction is carried out at a temperature of less thanabout 60° C., 50° C., 40° C., or even 30° C., with the reaction in oneparticular embodiment being carried out at about room temperature (e.g.,about 20° C. or about 25° C.), using for exampleN,N-diisopropylethylamine (DIEA) as a base (e.g., about 1.5, about 1.75,about 2, or more molar equivalents thereof), and acetonitrile (CH₃CN) asa solvent (alone or in combination with water).

In various embodiments, the yield of compound of Formula III is about85%, about 90%, about 95% or more, and/or the purity thereof is about90%, about 95%, about 98% or more.

3. Bromination Step

In one embodiment, the compound of Formula IV, or a salt thereof, isprepared by brominating a compound of Formula V:

or salt thereof; wherein each X is independently selected from chloroand hydroxyl. In a particular embodiment, both of the X substituents arehydroxyl, while in another embodiment both of the X substituents arechloro.

In this regard it is to be noted that, in some instances, the resultingreaction mixture may contain both the di-bromo substituted compound ofFormula IV, as well as a bromo-chloro substituted analogue compound,which if present will be the minor reaction product. Generally, themolar ratio of the di-bromo compound to the bromo-chloro compound willbe, for example, about 95:1, about 96:1, about 97:1, about 98:1, ormore. More particularly, when a di-chloro compound of Formula V issubjected to bromination, the resulting reaction mixture may containboth the compound of Formula IV_(b) (wherein Y in Formula IV is bromo),as well as the compound of Formula IV_(c) (wherein Y in Formula IV ischloro):

the molar ratio of the two compounds being as noted above.

The brominating agent for the reaction is selected from among knownbromination agents that, when contacted with the compound of Formula Vunder appropriate reaction conditions, results in the formation of avolatile byproduct, and more specifically a byproduct that can beremoved from the reaction mixture by distillation. In this regard, it isgenerally believed that removal of these byproducts from the mixture, asthe reaction is carried out, enables the equilibrium of the reaction tobe better controlled, such that the reaction favors halogen (i.e.,bromine) exchange at both locations, and more particularly that both Xmoieties in the compound of Formula V (i.e., both chlorine atoms in thecompound of Formula V_(c), or both hydroxyl moieties in the compound ofFormula V_(b)) are replaced with bromine atoms. Such an approach enablesgreater conversion to the desired reaction product, and reduces theamount of impurities that are otherwise formed.

Exemplary brominating agents include, but are not limited to, bromine,bromotrimethylsilane (or trimethylsilyl bromide (TMSBr)), phosphorusoxybromide (POBr₃), N-bromosuccinimide (NBS), and phosphorus tribromide(PBr₃).

In this regard it is to be noted that the brominating agent may be addedto the reaction mixture, or alternatively may be formed in situ, usingmethods generally known in the art. For example, TMSBr could be made insitu by the addition of trimethylsilyl chloride (TMSCl) and sodiumbromide (NaBr), or another alkali metal bromide (e.g., KBr, LiBr, MgBr₂,ZnBr₂, or tetraalkylammonium bromide), to the reaction mixture.

Although the particular process conditions, including reaction time,temperature, solvent, reagent, amount of reagent(s), order of reagentaddition, pH, etc. may be selected in order to optimize reaction productpurity and/or yield, in particular the compound of Formula V will becontacted with from about 2 to about 7 molar equivalents of thebrominating agent, and more typically will be contacted with from about2.5 to about 6, or from about 3 to about 5, molar equivalents of thebrominating agent, with about 3.5 equivalents of brominating agent beingused in one particular embodiment, the brominating agent being added ina single aliquot or in multiple aliquots over a period of time.Additionally, or alternatively, reaction may be carried out at atemperature of from about 65° C. to about 80° C., or from about 70° C.to about 75° C., using for example acetonitrile (CH₃CN) as a solvent,for about 15 hours to about 20 hour, or about 16 hours to about 18hours.

In various embodiments, conversion of the compound of Formula V to thecompound of Formula IV is about 85%, about 90%, about 95% or more.

4. Chlorination Step

The compound of Formula IV, or salt thereof, may be prepared by directlybrominating the compound or salt of Formula V, using for examplephosphorus oxybromide or phosphorus tribromide, or alternatively acompound of Formula V_(b) or a salt thereof, below. In one particularembodiment, however, the compound of Formula IV, or salt thereof, isprepared by first chlorinating the compound of Formula V_(b):

or a salt thereof, to form a compound of Formula V_(c):

or a salt thereof, and then brominating the compound or salt of FormulaV_(c) to form the compound or salt of Formula IV as detailed above.

The particular process conditions, including reaction time, temperature,solvent selection, reagent, amount of reagent(s), order of reagentaddition, pH, etc. may be selected in order to optimize reaction productpurity and/or yield. For example, in various embodiments the compound ofFormula V_(b) will be contacted with from about 1.5 to about 5 molarequivalents of the chlorinating agent, and more typically will becontacted with from about 2 to about 4, or from about 2.5 to 3.5, molarequivalents of the chlorinating agent, with about 3 equivalents ofchlorinating agent being used in one particular embodiment. In these orother embodiments, suitable chlorinating agents include, for example,phosphorus oxychloride (POCl₃) and phosphorus trichloride (PCl₃), amongothers. In these or still other embodiments, the reaction may be carriedout neat, the chlorinating agent (e.g., POCl₃) being added with anappropriate amount of base, such as about 1, about 1.1, about 1.2, ormore molar equivalents of for example 2,6-lutidine or N,N-dimethylaniline, in the absence of a solvent. Alternatively, selection of a baseand/or solvent (e.g., 2,6-lutidine with toluene as a solvent) may enablethrough-processing to be achieved, as further discussed elsewhereherein.

5. Pyrimidine Synthesis Step

In accordance with the present disclosure, the pyrimidine compound ofFormula V_(b), or salt thereof, is prepared by cyclizing a compound ofFormula VI_(b):

or a salt thereof. The process comprises contacting the compound ofFormula VI_(b), or salt thereof, with formamidine, and more particularlya salt thereof, including for example an acetate salt (i.e., formamidineacetate).

The particular process conditions, including reaction time, temperature,solvent selection, reagent, amount of reagent(s), order of reagentaddition, pH, etc. may be selected in order to optimize reaction productpurity and/or yield. For example, in various embodiments, the reactionmay be carried out in an alcohol solvent (e.g., methanol). In these orother embodiments, the compound of Formula VI_(b), or salt thereof, iscontacted with from about 1 to about 1.25 molar equivalents of theformamidine, and more typically will be contacted with from about 1 toabout 1.15, or from about 1 to about 1.05, molar equivalents of theformamidine, with about 1.05 equivalents of formamidine being used inone particular embodiment. Additionally, about 2, about 2.5, about 3, ormore molar equivalents of a base, such as NaOMe, may also be used in thereaction.

In various embodiments, the yield of the compound of Formula V_(b), orsalt thereof, is about 75%, about 80%, about 85% or more.

6. Conjugate Addition and Enzymatic Resolution Steps

Additionally, the compound of Formula VI_(b), or a salt thereof, isprepared by contacting crotononitrile with malonate to form an isomericmixture of a compound of Formula VI_(a) and a compound of FormulaVI_(b):

or salts thereof; and separating the compound or salt of Formula VI_(b)from the compound or salt of Formula VI_(a).

The particular process conditions, including reaction time, temperature,solvent selection, reagent, amount of reagent(s), order of reagentaddition, pH, etc. may be selected in order to optimize reaction productpurity and/or yield. For example, in various embodiments, the reactionof crotononitrile with malonate may be carried out in an alcohol solvent(e.g., methanol), or in a solvent such as tetrahydrofuran (THF). Inthese or other embodiments, the crotononitrile is contacted with fromabout 1 to about 1.5 molar equivalents of the malonate, and moretypically will be contacted with from about 1.05 to about 1.4, or fromabout 1.1 to about 1.3, molar equivalents of the malonate, with about1.1 equivalents of malonate being used in one particular embodiment.Additionally, from about 0.2 to about 0.8, or from about 0.4 to about0.6, molar equivalents of a base, such as sodium methoxide (NaOMe),sodium tert-pentoxide (or sodium tert-amylate, t-AmONa), and potassiumtert-pentoxide, may be added, with about 0.5 molar equivalents of basebeing used in one particular embodiment.

In various embodiments, the yield of the compound of formula VI_(a), orsalt thereof, is about 70%, about 75%, about 80% or more.

The compound of Formula VI_(b), or salt thereof, may be separated fromthe compound of Formula VI_(a), or salt thereof, using techniquesgenerally known in the art for the separation of isomers. In oneparticular embodiment, however, the compound of Formula VI_(b), or saltthereof, is separated from the isomeric mixture containing it and thecompound of Formula VI_(a), or salt thereof, by enzymatic resolution.Enzymatic resolution of the isomeric mixture may be achieved usingtechniques generally known in the art, including for example contactingthe isomeric mixture with a suitable lipase enzyme, in order toselectively hydrolyze an ester moiety of the compound of Formula VI_(a),or salt thereof, such that the compound of Formula VI_(b), or saltthereof, may be separated from the hydrolyzed compound. Suitable lipaseenzymes include, for example, those enzymes originated from amicroorganism of Candida, such as Candida cylindracea and Candidarugosa, a microorganism of Chromobacterium chocolatum, pig liver and athermophilic microorganism. Other suitable lipase enzymes are referencedin, for example, WO 2013/173736 (the entire contents of which areincorporated herein by reference for all relevant and consistentpurposes), as well as in Examples 2b and 2c herein. Alternatively, andmore particularly, enzymatic resolution of the isomeric mixture may beachieved by contacting the isomeric mixture with a suitable nitrilaseenzyme, in order to selectively hydrolyze the nitrile moiety of thecompound of Formula VI_(a), or salt thereof, such that the compound ofFormula VI_(b), or salt thereof, may be separated from the hydrolyzedcompound. Suitable nitrilase enzymes include, for example, the enzymereferenced in Example 2a, 2d and 2e herein.

The particular process techniques and conditions for the separation, andmore particularly the enzymatic resolution, of the compound or salt ofFormula VI_(b) from the compound or salt of Formula VI_(a), includingenzyme type, reaction time, temperature, solvent selection, reagent,amount of reagent(s), order of reagent addition, pH, etc. may beselected in order to optimize desired product purity and/or yield and/orreaction time. For example, in various embodiments, a mixture comprisingthe compounds of Formulas IV_(a) and IV_(b), or salts thereof, anitrilase enzyme, a solvent (such as water), a base (such as NaOH),and/or a buffer (such as KH₂SO₄ or K₂SO₄ or Na₂B₄O₇.10H₂O), may be usedto carry out the enzymatic resolution at about room temperature (e.g.,about 20-25° C.), over a period of about 24 hour, about 36 hours, about48 hours or more, with a period of from about 24 to about 48 hour beingtypically used in one or more embodiments.

In various embodiments, the yield of the compound of formula VI_(b), orsalt thereof, is about 30%, about 35%, about 40%, about 45% or more.

7. Through-Process Improvements and Overall Process Efficiency

For purposes of illustration, Scheme 4 below generally illustrates arepresentative embodiment of the process of the present disclosure, aswell as various compounds and intermediates encompassed by the presentdisclosure. More detailed embodiments, including specific processconditions and regents, are further provided in the Examples thatfollow. Those skilled in the art will appreciate that other reactionconditions, including reagents, reagent concentrations or molarequivalents, solvents, reaction temperature, reaction duration, etc., aswell as needed work-up (e.g., acid or base treatment), may be usedconsistent with the present process, in order to obtained the desiredcompounds and intermediates, without departing from the intended scopeof the present disclosure. Accordingly, the details presented hereshould not be viewed in a limiting sense.

It is to be noted that the process of the present disclosure isparticularly advantageous because two or more of the process steps, asillustrated for example in Scheme 4 above, may be carried out in seriesor sequence, without isolation of the intermediate reaction product.

In one particular embodiment, after the chlorination of the compound ofFormula V_(b), or salt thereof, the resulting compound of Formula V_(b),or salt thereof, is not isolated before it is subjected to brominationto form the compounds of Formula IV IV_(b) and IV_(c)), or saltsthereof. In this or another particular embodiment, the compounds ofFormula IV (i.e., IV_(b) and IV_(c)), or salts thereof, are not isolatedafter the bromination of the compound of Formula V_(b), or salt thereof,before reaction with the piperazine compound, as detailed above. Inthose embodiments wherein this three-step reaction sequence is carriedout without isolation of the noted intermediates (i.e., chlorination,bromination and piperazine addition reactions are carried out withoutisolation of the compounds of Formula V_(c), IV_(b)/IV_(c) and III, orsalts thereof, respectively), the average yield is typically about 80%,about 85%, about 90%, about 95% or more. In this or yet anotherparticular embodiment, the isomeric mixture comprising the compounds ofFormula VI_(a) and Formula VI_(b), or salts thereof, is not isolatedfrom the reaction product mixture prior to further separation of thecompound of Formula VI_(b) or salt thereof, from the compound of FormulaVI_(a) or salt thereof; that is, the compounds of Formula VI_(a) andFormula VI_(b), or salts thereof, are not isolated prior to reaction ofthe compound of Formula VI_(a) or salt thereof with a suitable enzyme(e.g., a nitrilase enzyme), in order to separate the compound of FormulaVI_(b) or salt thereof from it.

Accordingly, the present disclosure advantageously provides or enablesthe above-noted through-process reaction steps to be carried out, thuseliminating the need to isolate multiple reaction intermediates (e.g.,chlorination/bromination being performed through-process,bromination/piperazine addition being performed through-process,chlorination/bromination/piperazine addition being performedthrough-process, the enzymatic resolution being performedthrough-process, or all of these noted reactions steps being performedthrough-process).

In one exemplary embodiment of the present process, all of theabove-noted through process steps are utilized; that is, the enzymaticresolution step, as well as the chlorination/bromination/piperazineaddition steps, are performed through-process, wherein the variousreaction products being formed by each step are not be isolated beforethe next reaction step is carried out. The present process thereforeadvantageously enables significant improvements in process efficiency.For example, the average duration of the overall production cycle of thepresent process (as illustrated, for example, by Scheme 4) is reduced,as compared for example to the average duration of the overallproduction cycle for such a process that does not utilize thesethrough-process advantages to prepare an ester substituted analogcompound (as illustrated, for example, by Scheme 1), by about 30%, about40%, about 50%, about 60%, about 70%, or more, due to fewer processsteps being utilized (e.g., fewer isolation steps), and/or shorterreaction times (e.g., less time needed for enzymatic resolution using anitrilase enzyme, as compared for example to enzymatic resolution usinga lipase enzyme). In another embodiment, enzymatic resolution using anitrilase enzyme at elevated pH (for example pH about 9.2) exhibitsabout double reaction rate and higher selectivity (E) as compared tonitrilase resolution having starting pH about 7.2 or resolution using alipase enzyme.

8. Exemplary Embodiments

In a first exemplary embodiment of the present disclosure, the compoundof Formula I:

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group,is prepared by a process comprising: (a) contacting a compound ofcompound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group, to form a compound of Formula III:

or a salt thereof; and, (b) contacting the compound of Formula III, or asalt thereof, with a metalating agent to form the compound of Formula I,or a salt thereof.

In one aspect of the first exemplary embodiment, R¹ is H, or is an aminoprotecting group selected from t-butoxycarbonyl, benzyloxycarbonyl, andfluorenylmethyloxycarbonyl. In another aspect, Y is bromo. In anotheraspect, Lv is hydrogen or halogen. In another aspect, the compound ofFormula IV, or a salt thereof, is contacted with about 1 to about 1.5,or about 1.1 to about 1.2, molar equivalents of the piperazine compound,and in another aspect this reaction is carried out at about roomtemperature. In another aspect, the compound of Formula III, or a saltthereof, is contacted with about 1 to about 1.5, or about 1.05 to about1.2, molar equivalents of the metalating agent, and in another aspectthe metalating agent is a Grignard reagent selected from anorganomagnesium halide and an organolithium reagent.

In a second exemplary embodiment of the present disclosure, the compoundof Formula I:

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group,is prepared by a process comprising: (a) brominating a compound ofFormula V:

or salt thereof, wherein each X is independently selected from chloroand hydroxyl, to form a compound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo; (b)contacting the compound of Formula IV, or a salt thereof, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group, to form a compound of Formula III:

or a salt thereof; and, (c) contacting the compound of Formula III, or asalt thereof, with a metalating agent to form the compound of Formula I,or a salt thereof.

In one aspect of the second exemplary embodiment, R¹ is H, or is anamino protecting group selected from t-butoxycarbonyl,benzyloxycarbonyl, and fluorenylmethyloxycarbonyl. In another aspect, Xis chloro. In another aspect, Y is bromo. In another aspect, Lv ishydrogen or halogen. In another aspect, the compound of Formula V, or asalt thereof, is contacted with about 2 to about 7, or about 3 to about5, molar equivalents of a brominating agent, and in another aspect thebrominating agent is trimethylsilyl bromide. In another aspect, thebromination reaction is carried out at about 70° C. to about 75° C., andin another aspect distillation is used to remove volatile byproducts. Inanother aspect, the compound of Formula IV, or a salt thereof, iscontacted with about 1 to about 1.5, or about 1.1 to about 1.2, molarequivalents of the piperazine compound, and in another aspect thisreaction is carried out at about room temperature. In another aspect,the compound of Formula III, or a salt thereof, is contacted with about1 to about 1.5, or about 1.05 to about 1.2, molar equivalents of themetalating agent, and in another aspect the metalating agent is aGrignard reagent selected from an organomagnesium halide and anorganolithium reagent. In another aspect, the compound of Formula IV, orsalt thereof, is not isolated after the bromination reaction and beforereaction with the piperazine compound.

In a third exemplary embodiment of the present disclosure, the compoundof Formula I:

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group,is prepared by a process comprising: (a) chlorinating a compound ofFormula V_(b):

or a salt thereof, to form a compound of Formula V_(c):

or a salt thereof; (b) brominating the compound of Formula V_(c), orsalt thereof, to form the compound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo; (c)contacting the compound of Formula IV, or a salt thereof, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group, to form a compound of Formula III:

or a salt thereof; and, (d) contacting the compound of Formula III, or asalt thereof, with a metalating agent to form the compound of Formula I,or a salt thereof.

In one aspect of the third exemplary embodiment, R¹ is H, or is an aminoprotecting group selected from t-butoxycarbonyl, benzyloxycarbonyl, andfluorenylmethyloxycarbonyl. In another aspect, Y is bromo. In anotheraspect, Lv is hydrogen or halogen. In another aspect, the compound ofFormula V_(b), or a salt thereof, is contacted with about 1.5 to about5, or about 2 to about 4, molar equivalents of a chlorinating agent, andin another aspect the chlorinating agent is phosphorus oxychloride. Inanother aspect, the compound of Formula V, or a salt thereof, iscontacted with about 2 to about 7, or about 3 to about 5, molarequivalents of a brominating agent, and in another aspect thebrominating agent is trimethylsilyl bromide. In another aspect, thebromination reaction is carried out at about 70° C. to about 75° C., andin another aspect distillation is used to remove volatile byproducts. Inanother aspect, the compound of Formula IV, or a salt thereof, iscontacted with about 1 to about 1.5, or about 1.1 to about 1.2, molarequivalents of the piperazine compound, and in another aspect thisreaction is carried out at about room temperature. In another aspect,the compound of Formula III, or a salt thereof, is contacted with about1 to about 1.5, or about 1.05 to about 1.2, molar equivalents of themetalating agent, and in another aspect the metalating agent is aGrignard reagent selected from an organomagnesium halide and anorganolithium reagent. In another aspect, the compound of Formula IV, orsalt thereof, is not isolated after the bromination reaction and beforereaction with the piperazine compound. In another aspect, the compoundof Formula V_(c), or salt thereof, is not isolated after thechlorination reaction and before the bromination reaction.

In a fourth exemplary embodiment of the present disclosure, the compoundof Formula I:

or a salt thereof, wherein R¹ is hydrogen or an amino protecting group,is prepared by a process comprising: (a) contacting crotononitrile withmalonate to form an isomeric mixture comprising a compound of FormulaVI_(a) and the compound of Formula VI_(b):

or salts thereof; (b) separating the compound of Formula VI_(b), or saltthereof, from the compound Formula VI_(a), or salt thereof, in theisomeric mixture; (c) contacting the separated compound of FormulaVI_(b), or salt thereof, with a formamidine salt to form the compound ofFormula V_(b):

or a salt thereof; (d) chlorinating the compound of Formula V_(b) or asalt thereof, to form a compound of Formula V_(c):

or a salt thereof; (e) brominating the compound of Formula V_(c), orsalt thereof, to form the compound of Formula IV:

or salt thereof, wherein Y is selected from chloro and bromo; (f)contacting the compound of Formula IV, or a salt thereof, with apiperazine compound having the structure:

or salt thereof, wherein Lv is a leaving group and R¹ is an aminoprotecting group, to form a compound of Formula III:

or a salt thereof; and, (g) contacting the compound of Formula III, or asalt thereof, with a metalating agent to form the compound of Formula I,or a salt thereof.

In one aspect of the fourth exemplary embodiment, R¹ is H, or is anamino protecting group selected from t-butoxycarbonyl,benzyloxycarbonyl, and fluorenylmethyloxycarbonyl. In another aspect, Yis bromo. In another aspect, Lv is hydrogen or halogen. In anotheraspect, the crotononitrile is contacted with about 1 to about 1.5, orabout 1.1 to about 1.3, molar equivalents of malonate. In anotheraspect, the compound of Formula VI_(b), or salt thereof, is separatedfrom the compound Formula VI_(a), or salt thereof, in the isomericmixture by enzymatic resolution, and in another aspect the compound ofFormula VI_(b), or salt thereof, is separated by contacting the isomericmixture with a nitrilase enzyme. In another aspect, the separatedcompound of Formula VI_(b), or salt thereof, is contacted with about 1to about 1.25, or about 1 to about 1.15, molar equivalents of aformamidine salt to form the compound of Formula V_(b), and in anotheraspect the formamidine salt is formamidine acetate. In another aspect,the compound of Formula V_(b), or a salt thereof, is contacted withabout 1.5 to about 5, or about 2 to about 4, molar equivalents of achlorinating agent, and in another aspect the chlorinating agent isphosphorus oxychloride. In another aspect, the compound of Formula V, ora salt thereof, is contacted with about 2 to about 7, or about 3 toabout 5, molar equivalents of a brominating agent, and in another aspectthe brominating agent is trimethylsilyl bromide. In another aspect, thebromination reaction is carried out at about 70° C. to about 75° C., andin another aspect distillation is used to remove volatile byproducts. Inanother aspect, the compound of Formula IV, or a salt thereof, iscontacted with about 1 to about 1.5, or about 1.1 to about 1.2, molarequivalents of the piperazine compound, and in another aspect thisreaction is carried out at about room temperature. In another aspect,the compound of Formula III, or a salt thereof, is contacted with about1 to about 1.5, or about 1.05 to about 1.2, molar equivalents of themetalating agent, and in another aspect the metalating agent is aGrignard reagent selected from an organomagnesium halide and anorganolithium reagent. In another aspect, the compound of Formula IV, orsalt thereof, is not isolated after the bromination reaction and beforereaction with the piperazine compound. In another aspect, the compoundof Formula V_(b), or salt thereof, is not isolated after thechlorination reaction and before the bromination reaction. In anotheraspect, the compounds of Formulas VI_(b) and VI_(a), or salts thereof,in the isomeric mixture are not isolated before enzymatic resolution.

B. AKT Inhibitor Synthesis

The present disclosure is still further directed to the use of thecompounds of Formula I, or a salt thereof, as an intermediate in thesynthesis of Ipatasertib (i.e.,(S)-2-(4-chlorophenyl)-1-(4-((5R,7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazin-1-yl)-3-(isopropylamino)-propan-1-one),as disclosed for example in U.S. Pat. No. 8,063,050 (see, e.g., Example14 therein). Scheme 5 below generally illustrates an embodiment of theprocess of the present disclosure, as well as various compounds andintermediates encompassed by the present disclosure, wherein thecompound of Formula I, or a salt thereof, is used to prepareIpatasertib, in protected or unprotected form, or a salt thereof.

In particular, the compounds of Formula I, or a salt thereof, may beused to prepare a compound of Formula IX, or a salt thereof (i.e.,Ipatasertib, in protected or unprotected form, or a salt thereof):

wherein R² is hydrogen or an amino protecting group, as definedelsewhere herein below, and more particularly as defined in the contextof R¹ above.

In this regard it is to be noted that various suitable reaction schemesand processes may be used in accordance with the present disclosure, inorder to convert the compound of Formula I, or a salt thereof, to acompound of Formula IX, or a salt thereof. In one particular embodiment,however, the process comprises first preparing the compound of FormulaI, or a salt thereof, as set forth above. The compound of Formula I, orsalt thereof, is then reduced to form a compound of Formula VII_(a):

or salt thereof. More particularly, the compound of Formula I, or saltthereof, is subjected to stereoselective reduction by contacting it witha reducing agent comprising a suitable enzyme, such as a ketoreductaseenzyme, and optionally a hydride source, as disclosed in for example WO2013/173784 (the contents of which are incorporated herein by referencefor all relevant and consistent purposes), in order to obtain the isomerof Formula VII_(a).

If R¹ is a protecting group, the compound of Formula VII_(a), or saltthereof, may be deprotected using means generally known in the art(e.g., reacting with a suitable acid, such as hydrochloric acid) to forma compound of Formula VII_(b),

or salt thereof. The compound of Formula VII_(b), or salt thereof, isthen contacted with a compound of Formula VIII:

or salt thereof, to obtain the compound of Formula IX. The coupling ofthe compound of Formula VII_(b), or salt thereof, with the compound orsalt of Formula VIII, may be achieved using means known in the art,and/or as disclosed in for example WO 2013/173784 or WO 2013/173779, andin one embodiment may include the use of a suitable coupling agent asdisclosed therein. Additionally, the method of making a compound ofFormula VIII, or salt thereof, is described in for example U.S. Pat. No.8,063,050 and WO 2013/173779. (The entire contents of U.S. Pat. No.8,063,050, WO 2013/173784, and WO 2013/17379 are incorporated herein byreference for all relevant and consistent purposes.)

C. Reaction Products and Intermediate Compounds

It is to be noted that the present disclosure is still further directedto one or more of the nitrile-substituted reaction product or reactionintermediate compounds, or salts thereof, prepared by the processesillustrated herein, including for example the compounds of FormulaeV_(b), V_(c), IV_(b), and/or III, or salts thereof, as defined hereinabove.

D. Definitions

With respect to the present disclosure, the following terms have themeanings set forth below.

“Acyl” means a carbonyl containing substituent represented by theformula —C(O)—R in which R is hydrogen, alkyl, a cycloalkyl, aheterocyclyl, cycloalkyl-substituted alkyl or heterocyclyl-substitutedalkyl wherein the alkyl, alkoxy, cycloalkyl and heterocyclyl areindependently optionally substituted and as defined herein. Acyl groupsinclude alkanoyl (e.g., acetyl), aroyl (e.g., benzoyl), and heteroaroyl(e.g., pyridinoyl).

The term “alkyl” as used herein refers to a saturated linear orbranched-chain monovalent hydrocarbon radical of one to twelve carbonatoms, and in another embodiment one to six carbon atoms, wherein thealkyl radical may be optionally substituted independently with one ormore substituents described herein. Examples of alkyl groups include,but are not limited to, methyl (Me, —CH₃), ethyl (Et, —CH₂CH₃), 1-propyl(n-Pr, n-propyl, —CH₂CH₂CH₃), 2-propyl (iPr, i-propyl, —CH(CH₃)₂),1-butyl (n-Bu, n-butyl, —CH₂CH₂CH₂CH₃), 2-methyl-1-propyl (i-Bu, ibutyl,—CH₂CH(CH₃)₂), 2-butyl (s-Bu, s-butyl, —CH(CH₃)CH₂CH₃),2-methyl-2-propyl (t-Bu, tbutyl, —C(CH₃)₃), 1-pentyl (n-pentyl,—CH₂CH₂CH₂CH₂CH₃), 2-pentyl (—CH(CH₃)CH₂CH₂CH₃), 3-pentyl(—CH(CH₂CH₃)₂), 2-methyl-2-butyl (—C(CH₃)₂CH₂CH₃), 3-methyl-2-butyl(CH(CH₃)CH(CH₃)₂), 3-methyl-1-butyl (—CH₂CH₂CH(CH₃)₂), 2-methyl-1-butyl(CH₂CH(CH₃)CH₂CH₃), 1-hexyl (—CH₂CH₂CH₂CH₂CH₂CH₃), 2-hexyl(CH(CH₃)CH₂CH₂CH₂CH₃), 3-hexyl (—CH(CH₂CH₃)(CH₂CH₂CH₃)),2-methyl-2-pentyl (C(CH₃)₂CH₂CH₂CH₃), 3-methyl-2-pentyl(—CH(CH₃)CH(CH₃)CH₂CH₃), 4-methyl-2-pentyl (CH(CH₃)CH₂CH(CH₃)₂),3-methyl-3-pentyl (—C(CH₃)(CH₂CH₃)₂), 2-methyl-3-pentyl(CH(CH₂CH₃)CH(CH₃)₂), 2,3-dimethyl-2-butyl (—C(CH₃)₂CH(CH₃)₂),3,3-dimethyl-2-butyl (CH(CH₃)C(CH₃)₂, 1-heptyl, 1-octyl, and the like.

The term “alkylene” as used herein refers to a linear or branchedsaturated divalent hydrocarbon radical of one to twelve carbon atoms,and in another embodiment one to six carbon atoms, wherein the alkyleneradical may be optionally substituted independently with one or moresubstituents described herein. Examples include, but are not limited to,methylene, ethylene, propylene, 2-methylpropylene, pentylene, and thelike.

The term “alkenyl” as used herein refers to a linear or branched-chainmonovalent hydrocarbon radical of two to twelve carbon atoms, and inanother embodiment two to six carbon atoms, with at least one site ofunsaturation, i.e., a carbon-carbon, sp² double bond, wherein thealkenyl radical may be optionally substituted independently with one ormore substituents described herein, and includes radicals having “cis”and “trans” orientations, or alternatively, “E” and “Z” orientations.Examples include, but are not limited to, ethylenyl or vinyl (—CH═CH₂),allyl (—CH₂CH═CH₂), 1-propenyl, l-buten-1-yl, 1-buten-2-yl, and thelike.

The term “alkynyl” as used herein refers to a linear or branchedmonovalent hydrocarbon radical of two to twelve carbon atoms, and inanother embodiment two to six carbon atoms, with at least one site ofunsaturation, i.e., a carbon-carbon, sp triple bond, wherein the alkynylradical may be optionally substituted independently with one or moresubstituents described herein. Examples include, but are not limited to,ethynyl (—C═CH) and propynyl (propargyl, —CH₂C═CH).

The term “alkoxy” refers to a linear or branched monovalent radicalrepresented by the formula —OR in which R is alkyl, alkenyl, alkynyl orcycloalkyl, which can be further optionally substituted as definedherein. Alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy,mono-, di- and tri-fluoromethoxy and cyclopropoxy.

“Amino” means primary (i.e., —NH₂), secondary (i.e., —NRH), tertiary(i.e., —NRR) and quaternary (i.e., —N⁺RRRX⁻) amines, that are optionallysubstituted, in which R is independently alkyl, alkoxy, a cycloalkyl, aheterocyclyl, cycloalkyl, -substituted alkyl or heterocyclyl substitutedalkyl wherein the alkyl, alkoxy, cycloalkyl and heterocyclyl are asdefined herein. Particular secondary and tertiary amines are alkylamine,dialkylamine, arylamine, diarylamine, aralkylamine and diaralkylaminewherein the alkyls and aryls are as herein defined and independentlyoptionally substituted. Particular secondary and tertiary amines aremethylamine, ethylamine, propylamine, isopropylamine, phenylamine,benzylamine, dimethylamine, diethylamine, dipropylamine anddiisopropylamine.

The terms “cycloalkyl,” “carbocycle,” “carbocyclyl” and “carbocyclicring” as used herein are used interchangeably and refer to saturated orpartially unsaturated cyclic hydrocarbon radical having from three totwelve carbon atoms, and in another embodiment three to eight carbonatoms. The term “cycloalkyl” includes monocyclic and polycyclic (e.g.,bicyclic and tricyclic) cycloalkyl structures, wherein the polycyclicstructures optionally include a saturated or partially unsaturatedcycloalkyl ring fused to a saturated, partially unsaturated or aromaticcycloalkyl or heterocyclic ring. Examples of cycloalkyl groups include,but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclohexenyl, cyclohexadienyl, cycloheptenyl,and the like. Bicyclic carbocycles include those having 7 to 12 ringatoms arranged, for example, as a bicyclo[4,5], [5,5], [5,6] or [6,6]system, or as bridged systems such as bicyclo[2.2.1]heptane,bicyclo[2.2.2]octane, and bicyclo[3.2.2]nonane. The cycloalkyl may beoptionally substituted independently with one or more substituentsdescribed herein.

The term “aryl” as used herein means a monovalent aromatic hydrocarbonradical of 6-20 carbon atoms derived by the removal of one hydrogen atomfrom a single carbon atom of a parent aromatic ring system. Arylincludes bicyclic radicals comprising an aromatic ring fused to asaturated, partially unsaturated ring, or aromatic carbocyclic orheterocyclic ring.

Exemplary aryl groups include, but are not limited to, radicals derivedfrom benzene, naphthalene, anthracene, biphenyl, indene, indane,1,2-dihydronapthalene, 1,2,3,4-tetrahydronapthalene, and the like. Arylgroups may be optionally substituted independently with one or moresubstituents described herein.

The terms “heterocycle”, “heterocyclyl” and “heterocyclic ring” as usedherein are used interchangeably and refer to a saturated or partiallyunsaturated carbocyclic radical of 3 to 12 membered ring atoms in whichat least one ring atom is a heteroatom independently selected fromnitrogen, oxygen and sulfur, the remaining ring atoms being C, where oneor more ring atoms may be optionally substituted independently with oneor more substituents described below. One embodiment includesheterocycles of 3 to 7 membered ring atoms in which at least one ringatom is a heteroatom independently selected from nitrogen, oxygen andsulfur, the remaining ring atoms being C, where one or more ring atomsmay be optionally substituted independently with one or moresubstituents described below. The radical may be a carbon radical orheteroatom radical. The term “heterocycle” includes heterocycloalkoxy.“Heterocyclyl” also includes radicals where heterocycle radicals arefused with a saturated, partially unsaturated, or aromatic carbocyclicor heterocyclic ring. Examples of heterocyclic rings include, but arenot limited to, pyrrolidinyl, tetrahydrofuranyl, dihydrofuranyl,tetrahydrothienyl, tetrahydropyranyl, dihydropyranyl,tetrahydrothiopyranyl, piperidino, morpholino, thiomorpholino,thioxanyl, piperazinyl, homopiperazinyl, azetidinyl, oxetanyl,thietanyl, homopiperidinyl, oxepanyl, thiepanyl, oxazepinyl, diazepinyl,thiazepinyl, 2-pyrrolinyl, 3-pyrrolinyl, indolinyl, 2H-pyranyl,4H-pyranyl, dioxanyl, 1,3-dioxolanyl, pyrazolinyl, dithianyl,dithiolanyl, dihydropyranyl, dihydrothienyl, dihydrofuranyl,pyrazolidinylimidazolinyl, imidazolidinyl, 3-azabicyco[3.1.0]hexanyl,3-azabicyclo[4.1.0]heptanyl, azabicyclo[2.2.2]hexanyl, 3H-indolylquinolizinyl and N-pyridyl ureas. Spiro moieties are also includedwithin the scope of this definition. The heterocycle may be C-attachedor N-attached where such is possible. For instance, a group derived frompyrrole may be pyrrol-1-yl (N-attached) or pyrrol-3-yl (C-attached).Further, a group derived from imidazole may be imidazol-1-yl(N-attached) or imidazol-3-yl (C-attached). Examples of heterocyclicgroups wherein 2 ring carbon atoms are substituted with oxo (═O)moieties are isoindoline-1,3-dionyl and 1, 1-dioxo-thiomorpholinyl. Theheterocycle groups herein are optionally substituted independently withone or more substituents described herein.

The term “heteroaryl” as used herein refers to a monovalent aromaticradical of a 5-, 6-, or 7-membered ring and includes fused ring systems(at least one of which is aromatic) of 5-10 atoms containing at leastone heteroatom independently selected from nitrogen, oxygen, and sulfur.Examples of heteroaryl groups include, but are not limited to,pyridinyl, imidazolyl, imidazopyridinyl, pyrimidinyl, pyrazolyl,triazolyl, pyrazinyl, tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl,oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl,benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl,phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl,oxadiazolyl, triazolyl, thiadiazolyl, thiadiazolyl, furazanyl,benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl,quinazolinyl, quinoxalinyl, naphthyridinyl, and furopyridinyl. Spiromoieties are also included within the scope of this definition.Heteroaryl groups may be optionally substituted independently with oneor more substituents described herein.

“Leaving group” refers to a portion of a first reactant in a chemicalreaction that is displaced from the first reactant in the chemicalreaction. Examples of leaving groups include, but are not limited to,hydrogen, halogen, hydroxyl groups, sulfhydryl groups, amino groups (forexample —NRR, wherein R is independently alkyl, alkenyl, alkynyl,cycloalkyl, phenyl or heterocyclyl and R is independently optionallysubstituted), silyl groups (for example —SiRRR, wherein R isindependently alkyl, alkenyl, alkynyl, cycloalkyl, phenyl orheterocyclyl and R is independently optionally substituted), —N(R)OR(wherein R is independently alkyl, alkenyl, alkynyl, cycloalkyl, phenylor heterocyclyl and R is independently optionally substituted), alkoxygroups (for example —OR, wherein R is independently alkyl, alkenyl,alkynyl, cycloalkyl, phenyl or heterocyclyl and R is independentlyoptionally substituted), thiol groups (for example —SR, wherein R isindependently alkyl, alkenyl, alkynyl, cycloalkyl, phenyl orheterocyclyl and R is independently optionally substituted), sulfonyloxygroups (for example —OS(O)₁₋₂R, wherein R is independently alkyl,alkenyl, alkynyl, cycloalkyl, phenyl or heterocyclyl and R isindependently optionally substituted), sulfamate groups (for example—OS(O)₁₋₂NRR, wherein R is independently alkyl, alkenyl, alkynyl,cycloalkyl, phenyl or heterocyclyl and R is independently optionallysubstituted), carbamate groups (for example —OC(O)₂NRR, wherein R isindependently alkyl, alkenyl, alkynyl, cycloalkyl, phenyl orheterocyclyl and R is independently optionally substituted), andcarbonate groups (for example —OC(O)₂RR, wherein R is independentlyalkyl, alkenyl, alkynyl, cycloalkyl, phenyl or heterocyclyl and R isindependently optionally substituted). Example sulfonyloxy groupsinclude, but are not limited to, alkylsulfonyloxy groups (for examplemethyl sulfonyloxy (mesylate group) and trifluoromethylsulfonyloxy(triflate group)) and arylsulfonyloxy groups (for examplep-toluenesulfonyloxy (tosylate group) and p-nitrosulfonyloxy (nosylategroup)). Other examples of leaving groups include substituted andunsubstituted amino groups, such as amino, alkylamino, dialkylamino,hydroxylamino, alkoxylamino, N-alkyl-N-alkoxyamino, acylamino,sulfonylamino, and the like.

“Amino-protecting group” as used herein refers to groups commonlyemployed to keep amino groups from reacting during reactions carried outon other functional groups. Examples of such protecting groups includecarbamates, amides, alkyl and aryl groups, imines, as well as manyN-heteroatom derivatives which can be removed to regenerate the desiredamine group. Particular amino protecting groups are Ac (acetyl),trifluoroacetyl, phthalimide, Bn (benzyl), Tr (triphenylmethyl ortrityl), benzylidenyl, p-toluenesulfonyl, Pmb (p-methoxybenzyl), Boc(tertbutyloxycarbonyl), Fmoc (9-fluorenylmethyloxycarbonyl) and Cbz(carbobenzyloxy). Further examples of these groups are found in: Wuts,P. G. M. and Greene, T. W. (2006) Frontmatter, in Greene's ProtectiveGroups in Organic Synthesis, Fourth Edition, John Wiley & Sons, Inc.,Hoboken, N.J., USA. The term “protected amino” refers to an amino groupsubstituted with one of the above amino-protecting groups.

The term “substituted” as used herein means any of the above groups(e.g., alkyl, alkylene, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyland heteroaryl) wherein at least one hydrogen atom is replaced with asubstituent. In the case of an oxo substituent (═O) two hydrogen atomsare replaced. “Substituents” within the context of this inventioninclude, but are not limited to, halogen, hydroxy, oxo, cyano, nitro,amino, alkylamino, dialkylamino, alkyl, alkenyl, alkynyl, cycloalkyl,alkoxy, substituted alkyl, thioalkyl, haloalkyl (includingperhaloalkyl), hydroxyalkyl, aminoalkyl, substituted alkenyl,substituted alkynyl, substituted cycloalkyl, aryl, substituted aryl,heteroaryl, substituted heteroaryl, heterocycle, substitutedheterocycle, —NR^(e)Rr, —NR^(e)C(═O)R^(f), —NR^(e)C(═O)NR^(e)R^(f),—NR^(e)C(═O)OR^(f)—NR^(e)SO₂Rr, —OR^(e), —C(═O)R^(e)—C(═O)OR^(e),—C(═O)NR^(e)R^(f), —OC(═O)NR^(e)R^(f), —SR^(e), —SOR^(e), —S(═O)₂R^(e),—OS(═O)₂R^(e), —S(═O)₂OR^(e), wherein R^(e) and R^(f) are the same ordifferent and independently hydrogen, alkyl, substituted alkyl, alkenyl,substituted alkenyl, alkynyl, substituted alkynyl, cycloalkyl,substituted cycloalkyl, aryl, substituted aryl, heteroaryl, substitutedheteroaryl, heterocycle, substituted heterocycle.

The term “halo” or “halogen” as used herein means fluoro, chloro, bromoor iodo.

The term “a” as used herein means one or more.

Reference to “about” a value or parameter herein includes (anddescribes) embodiments that are directed to that value or parameter perse and in one embodiment plus or minus 20% of the given value. Forexample, description referring to “about X” includes description of X.

A “salt” of the various compounds and intermediates disclosed andprepared herein generally refer to essentially any salt form recognizedby one of skill in the art to be suitable in the manufacture of thecompounds and intermediates of the present disclosure. “Salt” as usedherein is understood to encompass, but not be limited to,“pharmaceutically acceptable salts,” and includes both acid and baseaddition salts. Exemplary salts include, but are not limited, tosulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate,bisulfate, phosphate, acid phosphate, isonicotinate, lactate,salicylate, acid citrate, tartrate, oleate, tannate, pantothenate,bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate,gluconate, glucuronate, saccharate, formate, benzoate, glutamate,methanesulfonate, ethanesulfonate, benzenesulfonate, p-toluenesulfonate,and pamoate 1,1′-methylene-bis-(2-hydroxy-3-naphthoate)) salts. Apharmaceutically acceptable salt may involve the inclusion of anothermolecule such as an acetate ion, a succinate ion or other counter ion.The counter ion may be any organic or inorganic moiety that stabilizesthe charge on the parent compound.

“Pharmaceutically acceptable acid addition salt” refers to those saltswhich retain the biological effectiveness and properties of the freebases and which are not biologically or otherwise undesirable, formedwith inorganic acids such as hydrochloric acid, hydrobromic acid,sulfuric acid, nitric acid, carbonic acid, phosphoric acid and the like,and organic acids may be selected from aliphatic, cycloaliphatic,aromatic, araliphatic, heterocyclic, carboxylic, and sulfonic classes oforganic acids such as formic acid, acetic acid, propionic acid, glycolicacid, gluconic acid, lactic acid, pyruvic acid, oxalic acid, malic acid,maleic acid, maloneic acid, succinic acid, fumaric acid, tartaric acid,citric acid, aspartic acid, ascorbic acid, glutamic acid, anthranilicacid, benzoic acid, cinnamic acid, mandelic acid, embonic acid,phenylacetic acid, methanesulfonic acid, ethanesulfonic acid,benzenesulfonic acid, p-toluenesulfonic acid, salicyclic acid and thelike.

“Pharmaceutically acceptable base addition salts” include those derivedfrom inorganic bases such as sodium, potassium, lithium, ammonium,calcium, magnesium, iron, zinc, copper, manganese, aluminum salts andthe like. Particularly base addition salts are the ammonium, potassium,sodium, calcium and magnesium salts. Salts derived from pharmaceuticallyacceptable organic nontoxic bases includes salts of primary, secondary,and tertiary amines, substituted amines including naturally occurringsubstituted amines, cyclic amines and basic ion exchange resins, such asisopropylamine, trimethylamine, diethylamine, triethylamine,tripropylamine, ethanolamine, 2-diethylaminoethanol, tromethamine,dicyclohexylamine, lysine, arginine, histidine, caffeine, procaine,hydrabamine, choline, betaine, ethylenediamine, glucosamine,methylglucamine, theobromine, purines, piperazine, piperidine,N-ethylpiperidine, polyamine resins and the like. Particularly organicnon-toxic bases are isopropylamine, diethylamine, ethanolamine,tromethamine, dicyclohexylamine, choline, and caffeine.

Compounds of the present invention, unless otherwise indicated, includecompounds that differ only in the presence of one or more isotopicallyenriched atoms. For example, compounds of the present invention, whereinone or more hydrogen atoms are replaced by deuterium or tritium, or oneor more carbon atoms are replaced by a ¹³C or ¹⁴C carbon atom, or one ormore nitrogen atoms are replaced by a ¹⁵N nitrogen atom, or one or moresulfur atoms are replaced by a ³³S, ³⁴S or ³⁶S sulfur atom, or one ormore oxygen atoms are replaced by a ¹⁷O or ¹⁸O oxygen atom are withinthe scope of this invention.

It is to be noted that the compounds detailed herein may contain one ormore chiral centers. Accordingly, if desired, such compounds can beprepared or isolated as pure stereoisomers (such as individualenantiomers or diastereomers, or as stereoisomer-enriched mixtures). Allsuch stereoisomers (and enriched mixtures) are included within the scopeof this disclosure, unless otherwise indicated. Pure stereoisomers (orenriched mixtures) may be prepared using, for example, optically activestarting materials or stereoselective reagents well-known in the art.Alternatively, racemic or stereoisomer-enriched mixtures of suchcompounds can be separated using, for example, chiral columnchromatography, chiral resolving agents, and the like.

It is to be further noted that all patents, patent applications,documents and articles cited herein are incorporated herein by referencein their entireties, for all relevant and consistent purposes.

While the processes and compounds of the present disclosure aredescribed herein in conjunction with particular the enumeratedembodiments, it is to be understood that they are not intended to limitthe scope of the disclosure to these embodiments. On the contrary, thedisclosure is intended to cover all alternatives, modifications, andequivalents. One skilled in the art will recognize many methods andmaterials similar or equivalent to those described herein, which couldbe used in the practice of the present process. Accordingly, the presentdisclosure is in no way limited to the methods and materials describedherein.

Additionally, in the event that one or more of the incorporatedliterature and similar materials differs from or contradicts thisdisclosure, including but not limited to defined terms, tern usage,described techniques, or the like, this disclosure controls.

EXAMPLES

The present disclosure can be further understood by reference to thefollowing Examples, which provide details for the preparation of thevarious compounds illustrated in the Scheme 4, above.

Example 1: Malonate Conjugate Addition

Dimethyl-2-(1-cyanopropan-2-yl)malonate

Sodium tert-pentoxide (65.7 g) was added to THF (900 g) and the mixturewas stirred for 30 minutes (mins). Dimethylmalonate (433 g) was addedand then the mixture was heated to 60-70° C. Crotononitrile (200 g) wasadded, while maintaining the internal temperature at 60-70° C. Themixture was stirred until reaction completion and then cooled to roomtemperature. Hydrochloric acid (HCl) in methanol (MeOH) was added untilthe mixture reached a pH of between 7-8, and then it was filtered. Thefilter cake was rinsed with THF (360 g). The collected solution orfiltrate was distilled to remove volatiles and afforded crudedimethyl-2-(1-cyanopropan-2-yl)malonate as a colorless to light yellowoil that was used directly in the next step. ¹H NMR (500 MHz, DMSO-d₆) δ3.67 (s, 6H), 3.51 (d, 1H, J=7.5 Hz), 2.68 (dd, 1H, J=5, 17 Hz), 2.54(dd, 1H, J=8, 17 Hz), 2.44 (m, 1H), 1.04 (d, 3H, J=7 Hz).

Example 2: Enzymatic Resolution

Exemplary enzymatic resolutions were carried out as further detailedbelow.

Example 2a—Dimethyl-(R)-2-(1-cyanopropan-2-yl)malonate Via Nitrilase

A 1500 mL four-necked round-bottom flask equipped with a KPG stirrer, athermometer and a dropping funnel was charged with 69.7 g (400 mmol)potassium sulfate and 5.44 g (40 mmol) potassium dihydrogenphosphate in800 mL deionized water (pH 4.85). Sodium hydroxide (3.87 g, 32% aqsolution) was added dropwise under stirring to a final pH of 7.2, andthen the solution was stirred for 15 mins. Dimethyl2-(1-cyanopropan-2-yl) malonate (199.5 g, 1.00 mol, 98% w/w) was addedand then the biphasic emulsion was stirred for 5 mins. at 20-25° C. (pHremaining unchanged).

The enantioselective hydrolysis was started by the addition of 39 mLnitrilase solution Nit-BX4-56-H6 (c-Lecta, Leipzig, Germany, catalogueno. 10906-3L; 500 U/mL) within 5 mins. The addition funnel was rinsedwith 8 mL deionized water, and the reaction mixture (pH 7.18) wasstirred at 20-25° C. When the enantiomeric excess of the retained, anddesired, nitrile reached 99.7% ee (after approx. 55% conversion; Eapprox. 50; after 43 hr; pH 6.93), the pH of the reaction mixture wasadjusted to 2.0 by the dropwise addition of approx. 96 g 25%hydrochloric acid (temp. less than 28° C.; heavy precipitation ofprotein). The emulsion/suspension was stirred for 10 mins. and thenreadjusted to pH 7.5 by adding approx. 85 g of 32% sodium hydroxidesolution (temp. less than 35° C.). The mixture was stirred for 10 mins.,and then 500 mL ethyl acetate was added and the suspension/emulsion wasstirred for another 5 min. The two phases were allowed to separate(approx. 3 mins.; protein precipitate largely in the organic phase), andthen were consecutively filtered over a filter cloth (9 cm, 20 um). Thefilter was rinsed with 500 mL ethyl acetate, the organic phases in thefiltrate combined, and then allowed to separate from the aqueous phase.The latter was extracted again with 1 L ethyl acetate. The combinedorganic phases were consecutively washed with 200 mL of 1 M sodiumbicarbonate and 100 mL deionized water, respectively, and evaporated todryness at 50° C./40 mbar/1.5 hr. to give 90.7 g (45%) ofdimethyl-(R)-2-(1-cyanopropan-2-yl)malonate as a light yellow oil: ¹HNMR (500 MHz, DMSO-d₆) δ 3.67 (s, 6H), 3.51 (d, 1H, J=7.5 Hz), 2.68 (dd,1H, J=5, 17 Hz), 2.54 (dd, 1H, J=8, 17 Hz), 2.44 (m, 1H), 1.04 (d, 3H,J=7 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ 168.43, 119.30, 55.36, 53.00,52.95, 30.41, 21.89, 17.17; [α]₄₃₆ ²⁰−2.2 (c=1, MeOH); HRMS calc'd. forC₁₆H₁₂NO₄ [M−H]⁻: 198.0772; found: 198.0770. Analytics: 95.3% GC(trimethylsilylated with BSTFA); 99.7% ee (GC on BGB-175; 30 m×0.25 mm,0.25 um; H2; 135 kPa; 90° C. to 150° C. with 2° C./min, to 180° C. with20° C./min; inj. 200° C.; det. 250° C.; inj. vol. 1 ml; split 15:1;30.77 min (R)-1, 31.09 min (S)-1; containing 2.5% ethyl acetate and<0.1% water).

Example 2b—Dimethyl-(R)-2-(1-cyanopropan-2-yl)malonate Via EsterHydrolysis Using Lipase CRL3

Dimethyl 2-(1-cyanopropan-2-yl) malonate (3.0 g, 15.1 mmol) was placedinto reactor followed by the addition of 21 mL 0.03 M acetate buffer pH5.2, 1.96 g potassium sulfate and 6.0 mL heptane. After 5 minutesstirring the addition of 60.0 mg cholesterol esterase from Candidacyclindracea [Roche, lot 10347322] (s/e 50) started the ester hydrolysisat room temperature (approx. 23° C.). The pH kept constant by theaddition of 1.0 N sodium hydroxide solution consuming 7.6 mL (7.6 mmol)during 50 h stirring. Ethyl acetate (30 mL) was added subsequently andthe reaction mixture was vigorously stirred 15 min forming an emulsion.1.5 g filtration aid (Dicalite®) was added subsequently and the reactionmixture was vigorously stirred for further 15 min. before filtrationthrough a filter-aid bed (Dicalite®). The two phases were separated. Theaqueous phase was extracted additionally twice with ethyl acetate (50mL). The organic phases were combined and washed three times with 50 mL100 mM potassium phosphate buffer pH 7.2. The organic phase was driedover magnesium sulfate, filtered and evaporated obtaining 1.26 g(R)-dimethyl 2-(1-cyanopropan-2-yl) malonate (99.6% purity; 42% yield)as a colorless oil. Enantiomeric excess=100% ee (HPLC-method: column:Chiralpak IA-3 150 mm*4.6 mm, 3 μm; isocratic A: 95% heptane+0.10% TFAB: 5% ethanol; flow 2 ml/min; 30° C.; 214 nm; 130 bar; retention times:(S)-nitrile 3.4 min, (R)-nitrile 3.89 min).

Example 2c—Dimethyl-(R)-2-(1-cyanopropan-2-yl)malonate Via EsterHydrolysis Using Lipase EL030 (III)

Dimethyl 2-(1-cyanopropan-2-yl) malonate (300 mg, 1.51 mmol) was placedinto a reactor followed by the addition of 29.7 mL 0.03 M MES buffer (pH6.2) and 300 mg β-cyclodextrin. After 5 mins. stirring, the addition of60.0 mg EL030 (III) [EUCODIS, lot 04804012SS0911] (s/e 5) started theester hydrolysis at room temperature (approx. 23° C.). The pH was keptconstant by the addition of 1.0 N sodium hydroxide solution, consuming1.05 mL (1.05 mmol) during 48 hr stirring. Chiral HPLC analysisdetermined an enantiomeric excess=100% eedimethyl-(R)-2-(1-cyanopropan-2-yl) malonate.

Example 2d—Dimethyl-(R)-2-(1-cyanopropan-2-yl)malonate Via Nitrilase atpH 9

A 350 mL four-necked round-bottom flask equipped with a KPG stirrer, athermometer and a dropping funnel was charged with 17.5 g (100 mmol)potassium sulfate, 1.36 g (10 mmol) potassium dihydrogenphosphate and1.325 g sodium carbonate (12.5 mmol) in 200 mL deionized water (pH 9.2)and the solution stirred for 15 min. Dimethyl 2-(1-cyanopropan-2-yl)malonate (50.0 g, 250 mmol, 98% w/w) was added over 5 min and then thebiphasic emulsion was stirred for 5 mins. at 20-25° C.

The enantioselective hydrolysis was started by the addition of 9.75 mL(4875 U) nitrilase solution Nit-BX4-56-H6 (c-Lecta, Leipzig, Germany,catalogue no. 10906-3L; 500 U/mL) within 2 mins. The addition funnel wasrinsed with 2 mL deionized water, and the reaction mixture was stirredat 20-25° C. When the enantiomeric excess of the retained, and desired,nitrile reached 99% ee (after approx. 53% conversion; E approx. 80;after 18 hr; pH 8.2), the pH of the reaction mixture was adjusted to 2.0by the dropwise addition of approx. 24.7 g 25% hydrochloric acid (temp.less than 27° C.; heavy precipitation of protein). Theemulsion/suspension was stirred for 10 mins. and then readjusted to pH7.5 by adding approx. 23.1 g of 32% sodium hydroxide solution (temp.less than 35° C.). The mixture was stirred for 10 mins., and then 125 mLethyl acetate was added and the suspension/emulsion was stirred foranother 5 min. The two phases were allowed to separate (approx. 3 mins.;protein precipitate largely in the organic phase), and then wereconsecutively filtered over a filter cloth (3 cm, 20 um). The filter wasrinsed with 125 mL ethyl acetate, the organic phases in the filtratecombined, and then allowed to separate from the aqueous phase. Thelatter was extracted again with 250 mL ethyl acetate. The combinedorganic phases were consecutively washed with 50 mL of 1 M sodiumbicarbonate and 25 mL deionized water, respectively, and evaporated todryness at 50° C./40 mbar/1.5 hr. to give 23.1 g (46.2%) ofdimethyl-(R)-2-(1-cyanopropan-2-yl)malonate as a light yellow oil in 99%ee and 94.9% GC (cf. Example 2a).

Example 2e—Dimethyl-(R)-2-(1-cyanopropan-2-yl)malonate Via Nitrilase atpH 9

To a 350 mL four-necked round-bottom flask equipped with a KPG stirrer,a thermometer and a dropping funnel containing 50.0 g dimethyl2-(1-cyanopropan-2-yl) malonate (250 mmol, 98% w/w) was added a solutionof 7.62 g (20 mmol) disodium tetraborate decahydrate and 17.5 g (100mmol) potassium sulfate in 200 mL deionized water (pH 9.3), and thebiphasic emulsion was stirred for 10 mins. at 20-25° C.

The enantioselective hydrolysis was started by the addition of 9.75 mL(4875 U) nitrilase solution Nit-BX4-56-H6 (c-Lecta, Leipzig, Germany,catalogue no. 10906-3L; 500 U/mL) within 2 mins. The addition funnel wasrinsed with 2 mL deionized water, and the reaction mixture was stirredat 20-25° C. When the enantiomeric excess of the retained, and desired,nitrile reached 99.8% ee (after 18 hr; pH 8.4), the pH of the reactionmixture was adjusted to 2.0 by the dropwise addition of approx. 27.7 g25% hydrochloric acid (temp. less than 27° C.; heavy precipitation ofprotein). The emulsion/suspension was stirred for 10 mins. and thenreadjusted to pH 8.0 by adding approx. 25.3 g of 32% sodium hydroxidesolution (temp. less than 32° C.). The mixture was stirred for 10 mins.,and then 125 mL methyl tert.butyl ether was added and thesuspension/emulsion stirred for another 5 mins. and then filtered over afilter cloth (5 cm, 20 um). The reaction vessel and the filter wererinsed with another 125 mL methyl tert.butyl ether, the organic phasesin the filtrate combined, and then allowed to separate from the aqueousphase. The latter was extracted again with 250 mL methyl tert.butylether. The combined organic phases were consecutively washed with 50 mLof 1 M sodium bicarbonate and 25 mL deionized water, respectively, andevaporated to dryness at 50° C./7 mbar/2 hr. to give 21.32 g (42.2%) ofdimethyl-(R)-2-(1-cyanopropan-2-yl)malonate as a light yellow oilin >99% ee and 95.7% GC (cf. Example 2a).

Example 3: Pyrimidine Synthesis

(R)-3-(4,6-Dihydroxypyrimidin-5-yl)butanenitrile. A reactor was chargedwith formamidine acetate (2.9 g) and MeOH (13.0 mL, 2.6 mL/g). Themixture was cooled to 5° C. under N₂, and then NaOMe (17.0 mL) wascharged to the reactor, resulting in a slight exotherm. After coolingback to 5° C., a solution of dimethyl (R)-2-(1-cyanopropan-2-yl)malonate(5.0 g) in MeOH (3.0 mL) was added slowly to the above suspension, thenthe reaction mixture was warmed to 25° C. Stirring was continued forapprox. 2 hrs, and then water (15.0 mL) was added and the pH wasadjusted to 5-7 by portion-wise addition of concentrated HCl (4.1 mL)while keeping the temperature below 30° C. The reaction mixture wasconcentrated under vacuum to approximately ⅓ of the starting volume, andthen sampled for MeOH content. Once MeOH was 10-20%, the slurry wascooled to 5° C. and the pH was adjusted to 4-6 by addition ofconcentrated HCl (1.25 mL, 0.25 mL/g). After stirring for 1 hr at 5° C.,the resulting solids were collected by filtration. The filter cake waswashed with cold water (15.0 mL, 3.0 vol, 5° C.) and dried in a vacuumoven at 70° C. overnight to give(R)-3-(4,6-dihydroxypyrimidin-5-yl)butanenitrile as an off-white solid(3.86 g, 86% yield): ¹H NMR (500 MHz, DMSO-d₆) δ 11.85 (bs, 2H), 7.96(s, 1H), 3.27 (m, 1H), 2.90 (dd, 1H, J=9, 17 Hz), 2.74 (dd, 1H, J=7, 17Hz), 1.17 (d, 1H, J=7 Hz), ¹³C NMR (125 MHz, DMSO-d₆) δ 164.15, 148.16,120.62, 103.17, 26.86, 21.07, 18.00; [α]₄₃₆ ²⁰−69.9 (c=1,N,N-dimethylacetamide); HRMS calc'd. for C₈H₈N₃O₂ [M−H]⁻: 178.0622,found: 178.0622.

Example 4: Chlorination-Bromination-S_(N)Ar Through-Process

tert-Butyl(R)-4-(6-bromo-5-(1-cyanopropan-2-yl)pyrimidin-4-yl)-piperazine-1-carboxylate

A reactor equipped with a reflux condenser was charged with(R)-3-(4,6-dihydroxypyrimidin-5-yl)butanenitrile (60.0 g, 334.9 mmol, 1eq.), toluene (720 mL, 12 vol.) and 2,6-lutidine (39.0 mL, 1.0 eq.) atroom temperature under N₂ atmosphere. The mixture was heated to 110° C.and POCl₃ (93.4 mL, 3 eq.) was slowly added, while maintaining thetemperature at 105-115° C. After 2 hrs, the starting material wasconsumed completely as detected by HPLC (>99%). The biphasic reactionmixture was cooled to 10-20° C. internal temperature. To a separatereactor was added 0.4M K₃PO₄ pH 7 buffer (300 mL, 5 vol.) at roomtemperature under N₂ atmosphere. The chlorination reaction mixture wasslowly added to the buffer solution while keeping the temperature atless than 30° C. Additionally, the pH of the quench mixture wasmaintained at 5-7 using 50% aq. NaOH (266 g, 4.4 wt.). Once the quenchwas complete, the layers were separated and the aqueous layer wasextracted with toluene (300 mL, 5 vol.). The combined organic phaseswere washed with 0.2 N aqueous HCl (250 mL, 4.2 vol). The organicsolution was washed with water (2×200 mL). The resulting solution wasdistilled under vacuum until the toluene level in the crude product wasless than 20 wt % as determined by GC analysis. An analytical sample wasobtained by chromatography of a concentrated sample on silica gel usingEtOAc/hexanes (1:1) as eluent.(R)-3-(4,6-dichloropyrimidin-5-yl)butanenitrile: ¹H NMR (500 MHz,DMSO-d₆) δ 8.83 (s, 1H), 3.93 (m, 1H), 3.11 (m, 2H), 1.43 (d, 3H, J=7Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ 161.40, 157.05, 133.07, 119.25, 32.57,20.84, 16.80; [α]₄₃₆ ²⁰+16.8 (c=1, MeOH); HRMS calc'd. for C₈H₈C₁₂N₃[M+H]⁺: 216.0092, found: 216.0092.

To the crude product was added acetonitrile (216.0 mL, 3.6 V). Thenitrogen line was configured so that it flowed over the reactorheadspace and exited after the distillation head. The reaction mixturewas then heated to 70-80° C. (target=75° C.) to produce a yellowsolution. Bromotrimethylsilane (90 mL, 1.5 V, 200 mol %) was then addedat 75° C. over 10 mins. This caused the reaction temperature to drop byapprox. 2-5° C. and distillation slowly began. After stirring at 75° C.for 30 mins., additional bromotrimethylsilane (66 mL, 1.1 V, 150 mol %)was added over 90 mins. at 75° C. This solution was allowed to stir attemperature for a total of 16-18 hr, and then a sample was pulled andanalyzed by HPLC for conversion. (If incomplete, additionalbromotrimethylsilane is added in 0.25 eq. increments, until the desiredlevel is attained.) An analytical sample was obtained by chromatographyof a concentrated sample on silica gel using EtOAc/hexanes (1:1) aseluent. (R)-3-(4,6-dibromopyrimidin-5-yl)butanenitrile: ¹H NMR (500 MHz,DMSO-d₆) δ 8.68 (s, 1H), 3.97 (m, 1H), 3.23 (dd, 1H, J=9, 17 Hz), 3.13(dd, 1H, J=8, 17 Hz), 1.44 (d, 3H, J=7 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ157.04, 137.23, 119.13, 36.00, 20.77, 16.73; [α]₄₃₆ ²⁰+39.5 (c=1, MeOH);HRMS calc'd. for C₈H₈Br₂N₃ [M+H]⁺: 303.9079, found: 303.9087.

The reaction mixture was cooled to 20-25° C. internal temperature anddiluted with acetonitrile (sufficient amount to obtain 0.5 M solution).Triethylamine (93.6 mL, 1.56 V, 200 mol %) and water (36.0 mL, 0.60 V)were then slowly added to the reaction and a sample was taken for pHmeasurement (1:100 dilution into water). If the pH is greater than 10,N—BOC-piperazine (71.5 g, 1.19 W, 115 mol %) is added and stirringcontinued at 20-25° C. If the pH is less than 10, triethylamine is addeduntil the desired pH is reached. The reaction was stirred at 20-25° C.for 16-18 hrs. A sample was pulled and analyzed by HPLC for conversion(G02855614≤2%). If no solids are present, tert-butyl(R)-4-(6-bromo-5-(1-cyanopropan-2-yl)pyrimidin-4-yl)piperazine-1-carboxylate(6.9 g, 0.12 wt) is used to seed. Water (720.0 mL, 18.0 V) was slowlyadded to precipitate the product. The mixture was cooled to 5° C. andstirred for at least 2 h and then filtered. The filter cake was washedwith room temperature water (360.0 mL, 6.0 V) and then placed in avacuum oven at 70-80° C., until a constant weight of off-white to whitepowder was obtained (123 g, 90% yield) of tert-butyl(R)-4-(6-bromo-5-(1-cyanopropan-2-yl)pyrimidin-4-yl)piperazine-1-carboxylate:¹H NMR (500 MHz, DMSO-d₆) δ 8.41 (s, 1H), 3.41 (bm, 4H), 3.24 (bm, 4H),3.08 (m, 2H), 1.48 (d, 3H, J=7 Hz), 1.41 (s, 9H); ¹³C NMR (125 MHz,DMSO-d₆) δ 168.23, 155.67, 154.44, 152.15, 125.08, 119.51, 79.62, 50.27,31.37, 28.52, 21.64, 17.66; [α]₄₃₆ ²⁰+78.9 (c=0.3, MeOH); HRMS calc'd.for C₁₇H₂₅BrN₅O₂ [M+H]⁺: 410.1186, found: 410.1180.

Example 5: Grignard Cyclization

tert-Butyl(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

A solution of tert-butyl(R)-4-(6-bromo-5-(1-cyanopropan-2-yl)pyrimidin-4-yl)piperazine-1-carboxylate(2.00 g) in anhydrous 2-MeTHF (5.00 mL) and anhydrous toluene (5.00 mL)was cooled to 5° C. in a 50 mL vessel. A solution of iPrMgCl (3.52 mL,105 mol %, 1.45 M in THF) was added over 4 hrs via a syringe pump whilemaintaining the batch temperature at 5±3° C. The orange-brown reactionmixture was quenched into aqueous NaHSO₄ solution over 5 mins., whilemaintaining the batch temperature at 20±5° C. The pH value of theaqueous layer was measured to be approx. 5 by pH paper. The mixture wasstirred for 30 mins. at 20±5° C. and the layers were separated. Theorganic layer was concentrated under vacuum (T_(j)=35° C., 100 mbar)until the solution concentration was 190-210 mg/g. The solution was thenseeded with tert-butyl(R)-4-(5-methyl-7-oxo-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate(0.10 g, 0.05 g/g) and stirred for 1 hr at 20-25° C. Degassed heptane(14.0 mL, 7.0 mL/g) was added over 2 hrs, and then the solution wasfiltered and washed with room temperature heptane/toluene (80:20, 6.0mL, 3.0 mL/g) and dried in a vacuum oven at 60° C., until a constantweight of tan-orange powder was obtained. The dried, crude ketone (1.25g, 1.0 wt), 2-propanol (5.0 mL, 4.0 mL/g) and water (1.25 mL, 1.0 mL/g)were charged to a 50 mL vessel. The slurry was degassed with N₂ for atleast 10 mins., then heated to 40° C. until all solids were dissolved.This solution was then cooled to 25° C. and seeded (0.06 g, 0.05 g/g)and stirred for at least 1 hr. The slurry was cooled to −5° C. over 1hr, then degassed water (6.04 mL, 4.83 mL/g) was added over 1 hr. Thisslurry was allowed to stir overnight, then filtered and washed with adegassed, pre-chilled (−5° C.) mixture of 2-propanol (1.5 mL, 1.2 mL/g)and water (3.5 mL, 2.8 mL/g). The solids were dried in a vacuum oven at70° C. until a constant weight of tan-orange powder was obtained. Theoverall yield for process was approximately 68-73% (1.1 g): ¹H NMR (500MHz, DMSO-d₆) δ 8.60 (s, 1H), 3.82 (m, 2H), 3.72 (m, 1H), 3.65 (m, 2H),3.50 (m, 2H), 3.42 (m, 2H), 2.90 (dd, 1H, J=7, 19 Hz), 2.25 (dd, 1H,J=2, 19 Hz), 1.41 (s, 9H), 1.19 (d, 3H, J=7 Hz); ¹³C NMR (125 MHz,DMSO-d₆) δ 205.75, 161.96, 158.89, 157.97, 154.34, 137.39, 79.67, 45.77,43.39, 43.25, 31.22, 28.52, 20.40; [α]₄₃₆ ²⁰+453.7 (c=1, MeOH); HRMScalc'd. for C₁₇H₂₄N₄O₃ [M+H]⁺: 333.1921, found: 333.1916.

Example 6: Comparative Example—Attempted Grignard Cyclization ofChloro-Nitrile Substituted Analogue Compound

Initially, the cyclization of a chloropyrimidine compound was attemptedusing transition metal catalysis (e.g., Pd, Rh, Ir) with a variety ofphosphine ligands. The des-chloro-pyrimidine was consistently found tobe the main product from the reaction.

Attempts at cyclizing the corresponding chloropyrimidine-nitrile, suchas those further detailed below, to the ketone were made using a varietyof transition metal pre-catalysts, including Ir, Ni, Pd, Rh and Ru.These pre-catalysts were complexed with a range of mono and bidendatephosphine ligands prior to the start of the reactions. The use ofadditives, such as Lewis and Bronsted acids, water, transition and phasetransfer catalysts were also tested. Reducing agents ranged frominorganic metals, such as zinc, to organic reducing agents, like formatesalts. Lastly, a diverse set of solvents were investigated, includingwater-miscible ethers, alcohols, polar aprotic to non-polar hydrocarbonsand carbonates. In all of these cases, the highest yield obtained fromthe screening experiments was approximately 20% of the desired ketoneproduct, with the remainder being starting material degradationproducts. The major byproduct formed in many of these reactions was thedes-chloro reduction product.

Example 6a: tert-butyl 4-(5-methyl-7-oxo-5,6-dihydrocyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

A slurry of Pd(OAc)₂ (6.1 mg, 0.10 equiv.), dimethylphenylphosphine(15.1 mg, 0.40 equiv.) and 1,2-dichloroethane (2.0 mL, 20.0 mL/g) wasstirred at 20-25° C. for 15 mins., then the solvent was removed invacuo. Zinc powder (35.7 mg, 2.0 equiv.), tert-butyl4-[6-chloro-5-(2-cyano-1-methyl-ethyl)pyrimidin-4-yl]piperazine-1-carboxylate(100.0 mg, 1.0 equiv.) and DMF (6.0 mL, 60.0 mL/g) were added and theslurry was heated at 110° C. for 18 hrs. The assay yield of the crudereaction mixture was 15.8% (14.4 mg).

Example 6b: tert-butyl 4-(5-methyl-7-oxo-5,6-dihydrocyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

A slurry of NiCl₂(DME) (24.0 mg, 0.40 equiv.), dimethylphenylphosphine(15.1 mg, 0.40 equiv.) and 1,2-dichloroethane (2.0 mL, 20.0 mL/g) wasstirred at 20-25° C. for 15 mins., then the solvent was removed invacuo. Zinc powder (35.7 mg, 2.0 equiv.), tert-butyl4-[6-chloro-5-(2-cyano-1-methyl-ethyl)pyrimidin-4-yl]piperazine-1-carboxylate(100.0 mg, 1.0 equiv.) and DMF (6.0 mL, 60.0 mL/g) were added and theslurry was heated at 110° C. for 18 hrs. The LC assay yield of the crudereaction mixture was 14.5% (13.2 mg).

Example 6c: tert-butyl 4-(5-methyl-7-oxo-5,6-dihydrocyclopenta[d]pyrimidin-4-yl)piperazine-1-carboxylate

A slurry of NiCl₂(DME) (24.0 mg, 0.40 equiv.), dimethylphenylphosphine(15.1 mg, 0.40 equiv.) and 1,2-dichloroethane (2.0 mL, 20.0 mL/g) wasstirred at 20-25° C. for 15 mins., then the solvent was removed invacuo. Zinc powder (35.7 mg, 2.0 equiv.), tert-butyl4-[6-chloro-5-(2-cyano-1-methyl-ethyl)pyrimidin-4-yl]piperazine-1-carboxylate(100.0 mg, 1.0 equiv.), Mg(OEt)₂ (13.2 mg, 0.40 equiv.) and DMF (6.0 mL,60.0 mL/g) were added and the slurry was heated at 110° C. for 18 hrs.The LC assay yield of the crude reaction mixture was 19.0% (17.3 mg).

Example 7: Comparative Example— Attempted Bromination Reaction Using HBr

Attempted bromination of the dichloropyrimidine nitrile with excess HBrand acetic acid or sodium bromide, and activation with methanesulfonicacid or copper catalysis, in a variety of solvents failed to afforduseful amounts of the corresponding dibromopyrimidine nitrile.

For example, bromination of dichloropyrimidine nitrile using excess HBrin acetic acid or NaBr with stoichiometric methanesulfonic acid inacetonitrile gave only incomplete conversion to the desireddibromopyrimidine with evidence of reversibility and productdecomposition based on HPLC analysis of the reaction mixtures.Alternatively, reaction of dichloropyrimidine nitrile with excess sodiumbromide and 5 mol % Cul as catalyst and 10 mol %N,N′-dimethylethylenediamine or 4,4′-di-tert-butyl-2,2′-bipyridine asligands in acetonitrile, dioxane or 1-butanol at 80-120° C. showedeither no desired product or competing addition of the solvent ordiamine ligand to the pyrimidine ring.

Additionally, it is to be understood that particular numerical valuesrecited herein, including for example reagent concentrations or ratios,reaction times, reaction temperatures, and the like, are intended todisclose and encompass all values there between, as well as all rangesthat may be created by the selection of any two values thereof. Forexample, reference to a reaction temperature of “about 20° C., 10° C.,about 0° C., or less” is to be understood to encompass reactiontemperature ranges of between about 0° C. and about 20° C., betweenabout 0° C. and about 10° C., between about 10° C. and about 20° C., orany two values there between.

With reference to the use of the words “comprise” or “comprises” or“comprising” in this patent application (including the claims),Applicants note that unless the context requires otherwise, those wordsare used on the basis and clear understanding that they are to beinterpreted inclusively, rather than exclusively, and that Applicantsintend each of those words to be so interpreted in construing thispatent application, including the claims below.

As used herein, reference to “a” or “an” means “one or more.”Throughout, the plural and singular should be treated asinterchangeable, other than the indication of number. For example,reference to “a compound” includes a single compound as well as one ormore additional compounds, reference to “a pharmaceutically acceptablecarrier” includes a single pharmaceutically acceptable carrier as wellas one or more additional pharmaceutically acceptable carriers, and thelike.

What is claimed is:
 1. A process for preparing a compound of FormulaV_(b):

or a salt thereof, the process comprising: (i) contacting crotononitrilewith malonate to form an isomeric mixture comprising a compound ofFormula VI_(a) and Formula VI_(b):

or a salt thereof; (ii) separating the compound of Formula VI_(b), or asalt thereof, from the compound of Formula VI_(a), or a salt thereof viaenzymatic resolution; and (iii) cyclizing a compound of Formula VI_(b),or a salt thereof.
 2. The process of claim 1, wherein the cyclization isachieved by contacting the compound or salt of Formula VI_(b) with aformamidine salt.
 3. The process of claim 1, wherein the enzymaticresolution is achieved by contacting the isomeric mixture comprising thecompound of Formula VI_(a) and Formula VI_(b), or salts thereof, with anitrilase enzyme or a lipase enzyme.
 4. The process of claim 3, whereinthe enzymatic resolution is achieved by contacting the isomeric mixturecomprising the compound of Formula VI_(a) and Formula VI_(b), or saltsthereof, with a nitrilase enzyme.
 5. The process of claim 3, wherein theenzymatic resolution is achieved by contacting the isomeric mixturecomprising the compound of Formula VI_(a) and Formula VI_(b), or saltsthereof, with a lipase enzyme.
 6. The process of any one of claims 1 to5, wherein the steps (ii) and (iii) are performed through-process. 7.The process of claim 1, wherein step (ii) is performed at a pH of about7.
 8. The process of claim 1, wherein step (ii) is performed at a pH ofabout 9.